SU1753320A1 - Device for transferring vibration from vibrator to article under test - Google Patents

Abstract

This invention relates to a vibration test technique. The purpose of the invention is to improve the accuracy of the transmission of linear oscillations. The device contains a rolling friction unit comprising two disks 5, 9 and balls 8 placed between them in the holder 7. The compression is provided by an elastic stretching element 11 and a rod 10 connected to it with a thread. Vibration is transmitted through a hollow adapter 2 with and with CA 8

Description

piece

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a flange 1 fixed on the table 3 of the vibration exciter, an intermediate element b with two cylindrical contact surfaces, forming which are mutually perpendicular, a friction training unit and a rod 10, on the threaded part of which the disk 9 and the test article 12 are screwed. The rod passes freely through the holes, made in the binder, intermediate element b and disk 5, and the elastic element 11 is placed inside adapter 2 and fixed on its flange 1, to reduce the effect of vibration of the test article 12 on the exciter, Flat elastic centering elements 13, their ends fixed on brackets 14 mounted on the housing of the vibration exciter. 1 hp f-ly, 2 ill.

The invention relates to testing equipment, namely, devices for transmitting linear oscillations from their source to the test object.

When the test item is directly attached to the moving element of the vibration exciter at frequencies of transverse resonances of the moving system of the vibration exciter, the product is subjected to transverse oscillations, which reduces the reliability of the test results. In this connection, vibration transmitting devices that reduce the level of transverse vibration loads are used in the stand structures, due to the fact that the eigenfrequencies of the object oscillations in the transverse direction in the new system are located below the operating range of test frequencies. When this condition is fulfilled, the transverse oscillations of the moving system of the exciter are not transmitted to the test article through the transversely compliant vibrating device.

A vibration test stand is known that contains vibration exciters connected to a platform for mounting the test article through spherical hinges in combination with translational friction pairs.

A vibration test stand is known, comprising a vibration exciter, a table for securing a test article and a vibration transmitting device located between the table and the moving element of the vibration exciter, having supporting points, mounted on the table and the moving element of the vibration exciter, freely inserted between the support points of the insert forming pairs with them, and elastic straps connecting the table with the movable element. This bench extends the range of testing to high chats, since the straps work only for stretching and therefore have

a large stock of dynamic stability.

It is also known vibrating device to the test stand, containing two flanges with cylindrical coaxial protrusions on surfaces facing each other, the end of one of the protrusions is flat, the other is a concave spherical, spherical liner located between the coaxial protrusions and interacting with their flat and concave spherical ends connecting elements in the form of elastic rods connected with flanges using spherical

hinges.

The closest in technical essence to the invention is a shaker, in which a device for transmitting vibrations from a vibration exciter to a test subject has a rolling friction unit comprising two discs and balls placed between them in a holder, as well as means for generating a pressing force. This device has a small transverse

stiffness and greater rigidity in the direction of vibration transmission, which allows extending the operating frequency range of the stand.

The disadvantage of the known shaker

is that the device has a higher bending stiffness compared to its transverse stiffness, since the preload is carried out evenly, and both disks are rigidly attached to the platform with the product, and the other to the moving part of the exciter. The frequency of the natural angular oscillations of the test product usually lies in the range of operating frequencies, and this leads to

significant distortion of the transmission of linear oscillations. Moreover, when the angular oscillations of the test product as a solid, it affects the moving part of the exciter vibro1, due to the fact that arising during angular oscillations of the product

bending moments are transmitted to the vibration exciter without modification through the rolling friction unit (bearing unit)

The purpose of the invention is to improve the accuracy of testing and reduce the effect of product vibrations on the vibration exciter.

The goal is achieved by the fact that the device for transmitting vibrations is equipped with a hollow adapter having a flange for ei to fasten an exciter on the table on one side, and a pad on the other, the rolling training unit is mounted on the pad via an intermediate element made with two cylindrical contacts the surfaces forming which are mutually perpendicular, and the means for creating a podzhati force include an elastic stretching element placed inside the adapter and fixed with one end on its flange, and A rod connected to its second end, which freely passes through openings made in a bolster, an intermediate element and in contact with the last disc, and is threaded, which is attached to another disc, in addition, the device is equipped with flat elastic elements for centering the bushing and brackets for fastening their ends on the casing of the vibration exciter

Figure 1 shows the proposed device, a General view; figure 2 - view And figure 1.

The device contains a flange 1 for fastening the hollow adapter 2 on the table 3 of the vibration exciter, the hollow adapter 2 is provided with a recess 4, on which the rolling friction unit is installed through the intermediate element 5. made with two cylindrical contact surfaces, which form mutually perpendicular

The rolling friction unit includes a disk 6 with balls 8 placed on it in a cage 7 and a disk 9 in contact with a rod 10 through thread, which includes an elastic stretch element 11, placed inside a hollow adapter 2 and fixed at one end on its flange 1 and the other - in the threaded hole of the test object 12, while the rod 10 freely passes through the holes made in the follower 4, the intermediate element 5 and the disk b

In addition, in order to reduce the effect of the vibration of the test object on the exciter, the device is equipped with flat elastic elements 13 for centering the subframe 4 and brackets 14

for fastening their ends on the casing of the vibration exciter.

To prevent the disc 9 and core 10 from loosening, locking nuts 15 and 16 are fitted.

The device works as follows.

The vibrostand is turned on, and the linear oscillations of the table 3 of the vibration exciter are transmitted through the device to the test object 12. At the same time, the vibration in the forward direction is transmitted to the test object 12 through flange 1, hollow adapter 2, bout 4, intermediate element 5, disk 6,

5 balls 8, disc 9 of the rolling friction unit and the threaded end of the rod 10, and in the opposite direction through the flange 1, the elastic stretch element 11 and the rod 10.

The device does not transmit to the subject

0 object 12 oscillations of the table 3 vibration exciter in the transverse direction at frequencies of transverse resonances of the moving element of the vibration exciter, since the resonant frequency of transverse oscillations

5, the test object 12, as a solid fixed on the device, due to its high compliance in the transverse direction does not exceed the lower chabtot range of testing. In this case

0, the test object 12, connected by a threaded rod 10 with an elastic stretching element 11 with a flange 1, is loaded in the resonant zone and remains stationary, and a backing 4 with an intermediate element

5 5 and the disk 6, moving along the balls 8 in the annular cage 7, is displaced in transverse directions. However, at the same time, the rolling friction forces on the shoulder, equal to the height of the hollow adapter 2 and subframe 4, create

0 momet, which leads to angular displacements of the moving element of the vibration-wizard and to its possible jamming in the gap with the body.

To prevent such corners

5 displacements are designed flat elastic elements 13, connecting the follower 4 in radial directions through the brackets 14 with the vibration exciter body and perceiving the forces of rolling friction

0 balls 8 per binder 4. At the frequencies of transverse resonances of the moving element of the vibration exciter, the lateral displacement of the table of the woofer 3 will be accompanied by its angular rotation around the center lying in the plane of attachment of the flat elastic elements 13 with the subgun 4.

This leads to rotation of the end face of the bolster 4 with the bend of flat elastic elements 13 and, in the absence of intermediate element 5, to uneven load on the balls 8 in the ring cage 7, to transfer through them the angular oscillations to the test object 12. With preliminary interaction of the bushing 4 with the intermediate element 5, with its angular rotations, it will roll with a flat end on the cylindrical surface of intermediate element 5 or in a perpendicular direction together with intermediate element 5 its cylinder will roll surface on the flat end of the disk 6.

 As a result of rotation of the hollow adapter 2 with the support 4 relative to the disk 6, the angular displacement of the moving element of the exciter is not transmitted to the test object 12. Also, the angular oscillations of the subject, on the basis of the rigidity of the vibration transmitting device, as in a resonant system, will not be excited when loading.

The flexural rigidity of the device is equal to the flexural rigidity of the elastic stretching element 11 and will be significantly lower than the intrinsic polyperic stiffness of the device. At the same time, the frequency of angular oscillations of the system of the test object (as a solid) —the vibrating-transmitting device will be lower than the frequency of transverse oscillations of this system, which determines the lower limit of the working range of test frequencies, thereby eliminating the angular resonance1 of the object on the device and increasing the accuracy of linear oscillations.

An increase in the accuracy of the transmission of linear oscillations is achieved in the invention also by eliminating the transfer to the test object of the rolling friction forces arising in the known device during lateral movement of the table 3, and the moments created by these forces on the shoulder,

equal to the distance from the rolling plane to the center of mass of the test object.

The proposed device is intended for vibration testing of objects in the frequency range of 5–2000 Hz with a maximum level of transmitted forces of up to 5,103 N. At the same time, running away allows the test object to be loaded at the same time in three mutually perpendicular directions.

Claims (2)

1. The device for transmission chose the vibration exciter of the tested product, containing a rolling friction unit, including two disks and placed between the HPMM in the cage, and a means for assembling effort, pressed against said node, characterized in that, in order to improve test accuracy, it is provided with a hollow an adapter blowing from one side of the flange for not just one standpoint, and on the other side of a flange, the rolling friction unit is mounted on the thumbguard through an intermediate element made with two cylindrical contact surfaces, forming which are mutually perpendicular, and the means for creating a clamped force include an elastic stretch element placed inside the adapter and fixed with one end on its flange, and connected to its other end a rod that freely passes through holes made in the binder, intermediate element and in contact with the last disk, and is made with a thread on which another disk is screwed. 2. Device pop. 1, characterized by the fact that. in order to reduce the effect of vibration of the product on the vibration exciter, it is provided with flat elastic elements for centering the bolster and brackets for fastening their ends on the body of the wicker. View And FIG. 2